Electronic differential controller
AssigneeU.S. Philips Corporation
InventorHenri J. Velo
Life of this patent
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Abstract
The invention relates to a differential controller comprising two transistors connected as a long-tailed pair with the base circuits of the transistors including resistors whose values are equal to the bulk resistances of the two transistors. The collector circuits of the two transistors include means for injecting currents into said resistors, which currents are proportional to the collector currents of the two transistors.
Claims11
An electronic differential controller comprising first and second transistors coupled together to form a differential amplifier with each transistor having an emitter connected to a point of constant voltage via an input signal current source, means for deriving an output signal from the collector circuit of one of said transistors, means coupling base electrodes of the first and second transistors to a control circuit for adjusting the currents in said transistors, said control circuit comprising first and second resistors having a first terminal connected to the base electrodes of the first and second transistors, respectively, and means for connecting a second terminal of said resistors together, and wherein the collector circuits of the first and second transistors include means for injecting currents into said resistors that are proportional to the collector currents flowing through the first and second transistors.
An electronic differential controller as claimed in claim 4 wherein the collector circuits of the first and the second transistor each include at least one semiconductor diode bridged by the base-emitter path of an auxiliary transistor, having a collector connected to the base electrode of the associated first or second transistor.
An electronic differential controller as claimed in claim 4 further comprising means connecting the collector of the first transistor to a point of constant potential via the series connection of third and fourth resistors with the junction point of said third and fourth resistors being connected to the collector of the second transistor via a fifth resistor, means connecting the collector of the second transistor to the junction point of sixth and seventh resistors connected in series between the base of the first transistor and the said point of constant potential, and means connecting the collector of the first transistor to the junction point of eighth and ninth series-connected resistors included between said point of constant potential and the base of the second transistor.
Dependencies are inferred from the claim text.